[kelnos]

That only makes sense for an online store that's going to ship you something, in which case asking for the destination ZIP code up front solves that problem.

For brick-and-mortar stores, the store can quite easily calculate the final price of an item on its own. Sales taxes do change on occasion, but likely less often than the pricing of the items themselves do, so there's no added burden in having to update them due to tax changes.

[tzs]

> That only makes sense for an online store that's going to ship you something, in which case asking for the destination ZIP code up front solves that problem

Tax boundaries do not follow zip code boundaries.

To actually find the right tax rate you need the full address, including suite or apartment number because there are cases where a tax boundary runs between different suites at the same street address.

Also this is not just for online stores that ship something. It also applies if you are selling a downloadable good like a game or music, or selling memberships to your site.

[astrange]

> Tax boundaries do not follow zip code boundaries.

Zip codes represent mail routes, so they're not actually polygons but a set of points (mailboxes), so they don't really even have boundaries.

The Census Bureau has polygons made from those points, but they're not official.

[heimidal]

FYI, ZIP code is not enough to calculate tax rate. You need city and county. 9,000 ZIP codes cross county borders.

Currently, consumers can generally tell if they are getting a reasonable price by comparing the MSRP they see in an ad against the price they see in store. For example, if the nationally advertised price of an Xbox is $500 and Best Buy has it for $500, I know I'm not being swindled.

But if the in-store price is $550? I guess I have to haul out my calculator and ask for the store's tax rate so I can determine whether or not Best Buy is ripping me off and I should take my business elsewhere.

Ideally, they'd show pre-tax price, tax rate, and calculated total price on every tag. Maybe, one day, we'll see action on this in a state or two, but I don't suspect it is high on the lists of any lawmakers.